Processing Machinery
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Excessive gel/gel particles in linear low-density polyethylene extruded products
Problem Phenomenon
Transparent or translucent gel particles (gel particles) are visible in extruded films or products, affecting product appearance and transparency.
Gel is resin particles that are not fully plasticized or are crosslinked.
Cause Analysis
(1) High molecular weight components in the raw material are not fully plasticized
(2) Barrel temperature is on the low side, and part of the resin is not completely melted
(3) Screw mixing effect is insufficient
(4) The raw material contains crosslinked or oxidized gel
(5) The screen mesh count is insufficient, and gel is not intercepted
Solution
(1) Appropriately increase barrel temperature to the higher value within the 190-250°C range
(2) Optimize screw design and add mixing elements
(3) Increase the screen mesh count to 80-120 mesh
(4) Select high-quality raw materials with low gel content
(5) Check whether crosslinked material is mixed into the regrind
Key Takeaway
Gel is caused by insufficient plasticization or raw material quality problems and needs to be solved from temperature control, screw design and raw material selection.
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